Black smoke rises from besieged Nairobi shopping mall: witness

NAIROBI (Reuters) - Black smoke was seen rising and several blasts were heard on Monday in the area of a Nairobi shopping mall where Islamist militants are holed up with hostages, a Reuters witness said.

Television images showed troops in camouflage running to new positions, while an armored personal carrier was also seen shifting position. Journalists and their cameras have been moved and no longer have a clear sight of the mall, but can see its perimeter.

"It is us who caused the explosion, we are trying to get in through the roof," one security official, who asked not to be named, told Reuters at the scene. There was no official comment.